What Lauryl Hydroxysultaine Actually Is
Lauryl hydroxysultaine sits on the same shelf as the better-known lauryl betaine, but it earns its place with a different headgroup. Where betaine carries a carboxylate, hydroxysultaine carries a sulfonate — and that one-atom swap changes how the molecule behaves in a real formulation. The full specification is on our lauryl hydroxysultaine product page (CAS 13197-76-7).
Commercial material is listed as CAS 13197-76-7, molecular formula C17H37NO4S, molecular weight 351.55, and EINECS 236-164-7. It comes as a light yellow, transparent liquid rather than a powder, with a density around 1.1 at 20 °C and water solubility near 680 g/L at the same temperature — effectively freely miscible, which is exactly what you want for a liquid surfactant concentrate. The boiling point is quoted around 350 °C at atmospheric pressure, so it stays stable through the heat of standard blending and filling. In the plant it is handled as a pumpable, easy-to-meter liquid surfactant that slots into the rest of a typical cleansing base without special equipment.
How It Differs From Lauryl Betaine
Both are zwitterionic (amphoteric) surfactants, so both stay positively charged in acid and negatively charged in base, and both are gentle on skin. The difference is the headgroup. The sulfonate in hydroxysultaine is a stronger acid than the carboxylate in betaine, which gives hydroxysultaine a wider effective pH range and, more importantly, better resistance to hard water and lime-soap formation. If you have ever watched a shampoo or body wash go thin and greasy in a high-calcium water supply, that is the exact failure mode a sultaine is there to prevent. Our lauryl betaine (CAS 683-10-3) is the natural companion when the water is softer and the cost target is tighter; hydroxysultaine is the upgrade when foam and viscosity have to hold up under stress.
What It Does in a Cleanser
The supplier data sheets the molecule with four jobs: foaming agent, thickening agent, conditioning agent, and calcium-soap dispersant. In shampoos, bubble baths, and facial cleansers those roles overlap in useful ways. As a foam booster it lifts the volume and creaminess of a sulfate-based system without adding much of its own cleansing, so the formulator can dial back the harsher primary surfactant. As a thickener it helps build the viscosity that makes a product feel substantial in the hand. As a conditioner it leaves a mild, soft after-feel, and as a calcium-soap dispersant it keeps soap scum from forming when the formula meets hard water in the shower or basin.
Safety is one of the reasons it shows up in baby and facial products. The material carries a risk coefficient of 1, is rated relatively safe, is noted as having no particular effect on pregnant users, and does not cause acne. Combined with its low skin and eye irritation, that makes it a routine choice wherever the claim on the pack is "mild" or "gentle."
In practice it is used at modest levels — often just a few percent of the total formula, sitting alongside the primary anionic — because its job is to modify the foam and the after-feel rather than to do the heavy lifting of cleansing. That small-dose role is also what keeps the cost impact low even when a formulator reaches for the sultaine instead of the cheaper betaine, since the upgrade is measured in tenths of a percent of the finished goods rather than in the bulk of the base.
Pairing It With the Rest of the Surfactant Bench
Hydroxysultaine is rarely the only surfactant in a formula, and the surrounding cast is worth knowing. The anionic workhorse in most cleansing systems is sodium lauroylsarcosinate (CAS 137-16-6), which hydroxysultaine stabilizes and boosts. Its building blocks and relatives — sarcosine (CAS 107-97-1) and N-oleoylsarcosine (CAS 110-25-8) — cover the sarcosinate side of the same mild-surfactant story. For preservation, ethylhexylglycerin (CAS 70445-33-9) is the usual booster that rides along in these systems to extend the preservative without raising the irritancy budget.
Where It Shows Up in Finished Systems
Once the surfactant base is set, the rest of the formula tends to pull from a predictable toolbox. Emollients such as squalane (CAS 111-01-3) and soybean lecithin (CAS 8002-43-5) cushion the after-feel so a wash does not leave skin tight, while humectants like urea (CAS 57-13-6) and D-trehalose dihydrate (CAS 6138-23-4) hold water in the stratum corneum after rinsing.
Active ingredients in the same wash-off products link back to the same bench. An acne wash leans on salicylic acid (CAS 69-72-7), an exfoliating cleanser on glycolic acid (CAS 79-14-1), and a brightening wash on kojic acid (CAS 501-30-4), alpha-arbutin (CAS 84380-01-8), or L-ascorbic acid (CAS 50-81-7). To keep all of that stable and skin-compatible, a pH adjuster such as citric acid anhydrous (CAS 77-92-9) closes the loop on the system.
Specifying and Sourcing
For most personal-care work the relevant checks are active content — the material is supplied as an aqueous solution, so confirm the solids or active percentage — plus color and clarity, pH, and residual-solvent profile. Because hydroxysultaine is a liquid, packaging is normally a drum or IBC with the usual polyethylene lining, and storage is the standard cool, dry, protected-from-freezing condition that keeps a surfactant concentrate stable across its shelf life.
Lauryl hydroxysultaine is a mature, well-understood ingredient, which means the buying decision comes down to consistency, documentation, and lead time rather than novelty. For teams building shampoos, body washes, facial cleansers, or bubble baths, keeping hydroxysultaine and its usual surfactant, emollient, and active companions on one reliable supply line removes a recurring sourcing headache and makes pilot-to-production scaling predictable.
